An alternative to hd gear mod

[BarHarborBasher]

Lol I'd have to say the mesh must've been perfect to not generate heat without lube... you must've been in a rush to run the beast lol...btw... it's 84 degrees out and the plastic on my j.d riding mower is 119 the yellow seat 137... the ground was up to 125 .. the car must acclimate within a couple minutes... maybe that's why my xl hasn't broke any plastic... I've been driving Iike a idiot with no consequence

[bbos12]

With the exception of pinion/spur, correct?


Sent from my iPhone using Tapatalk

[BarHarborBasher]

Lol I almost removed my spur cover the other day to check the temp because I can't stop playing with my new heat gun lol.. simple things amuse simple minds lol but I'm curious as well...

[84yoda]

Originally Posted by bbos12

With the exception of pinion/spur, correct?


Sent from my iPhone using Tapatalk

Correct.

[Tzicul]

I have done this mod on the front diff, also, where is still the original straight cut pinion. And after a tighter mesh there is no more clicking noise on hard braking because of those two chipped teeth. So, again, it is not a problem of ring/pinion itself, but a problem of a correct mesh and of some waaay undersised_fast_failing bearings!! Which this mod can only help on.

[Tzicul]

After countless runs on 6S I decided to check on my diffs and now I can confirm this mod is absolutely bulletproof. Not only for the gears themselves, but also for the bearings. There is almost no wear at all, especially on the outer one which is usually the first to fail. So my assumption the forces has a better distribution with three bearings mod is correct and they will definitely last much longer.

[Tzicul]

First transmission case. Because of THAT bearing Happily was only the bearing and the case, no other damages

[Tzicul]

Let me explain here, also, the idea behind this mod. I explained it in another thread, but it's better to have all the informations in one spot:

It's really simple what is happening with three bearing mod. Everybody says that new lip on the pinion is too thick, so the pinion is too far into the crown. I have to believe this as I never tried to install a HD pinion with two bearings. Let's suppose it is true, therefore we need to pull back the pinion as far is needed. Now, two bearings plus one original spacer mean 12.82mm, according to my measurements. And now consider that lip is not needed, that mean we will need 12.62mm for everything to be right. Ok, but three bearings mean only 12.00mm, which mean we are 0.62mm too short, or too far away from the crown. So we will need to add the necessary amount of shims to compensate. Of course, considering all the tolerances, maybe you will need more or less than 0.6mm, I needed 0.7mm. And maybe you'll need to add some shims behind the first bearing, near the C-clip. Also this is why you don't need to remove the lip, because you'll just need to add more shims to compensate.
I'm not saying removing the lip won't work, again, I never tried HD pinion on two bearings. And I'll never try because of the other good thing brought by this mod, you'll have the third bearing to take over all the forces, which mean you'll have less forces per bearing, hence all the bearings will last longer. And if one of them will fail, it won't be so catastrophic to the pinion.

[Axial Rose]

I guess I'm just stupid because I haven't built my YXL yet (I bought my kit and electronics months ago)

When I discovered the latest ADF (Axial design flaw) I wanted to just take a financial loss and get rid of this truck and lose the almost guaranteed frustration

But it's such a cool truck - I just couldn't sell it - and I can't have a truck this awesome and only run it on 4S or run it on 6S knowing I'm toasting it every time I punch it into a turn and kick up a monster-size wall of dirt (almost more fun than jumping, IMO)

I might get another kit and run one with each mod

• The Tzicul 3-bearing mod
• The BHB grind-the-pinion mod

My full size car will fit both trucks in the back and it would help me avoid the total bummer situation of being out there, having tons of fun bashing, have something break, and then not have a backup


Happy bashin everyone

PS - I also have plans for a 3D printed cover to help reduce debris from getting into the union between the driveshaft and the rear axle (although I really like the solution someone used with a plastic bottle cap)

[Tzicul]

Originally Posted by Axial Rose

I might get another kit

Damn! I never thought this way!! Pretty expensive backup, but, nevertheless, definitely can be an option.

Anyway, I can say that now, after all the modifications, it is a pretty reliable car. I just broke the idler bearing and the transmission's case, but I suppose that's because I forgot to change the original Axial bearing. Don't know how this happens, but it was the only one with metal sealing and all the rest are with rubber sealing

[84yoda]

Originally Posted by Axial Rose

3-bearing and BHB mod

How about run both?

I'm running both in a VP housing. But the front with a dhawk housing isn't able to run 3 bearings which is kinda lame, but oh well.

[Axial6768]

Originally Posted by Tzicul

Damn! I never thought this way!! Pretty expensive backup, but, nevertheless, definitely can be an option.

Anyway, I can say that now, after all the modifications, it is a pretty reliable car. I just broke the idler bearing and the transmission's case, but I suppose that's because I forgot to change the original Axial bearing. Don't know how this happens, but it was the only one with metal sealing and all the rest are with rubber sealing

That was the same bearing that gave up on my transmission case, you were lucky you didn't destroy the transmission gears like mine.

[Lavaheadache]

yea, when that bearing went in my case I lost 2 gears along with it

[Tzicul]

It seem more than a year passed by without doing anything to my diffs and I decided to make an inspection, bumper to bumper. And after all this time, incredible, everything looks just right. Only the outer bearings was a little loose so I changed them. But the pinions has almost no wear.

[Spunkybob]

I was trying to rack my brain around how this mod works.. and... I UNDERSTAND NOW!!! So by having LESS shims and the 3rd bearing the whole thing is slightly shorter. So that means the shaft/pinion "floats" in the diff housing. So when the 3 screws are tightened down there is a small gap between the screws and bearing allow the pinion/shaft to move freely and "settle" in the ideal spot for a good mesh. That is a great compromise because even if it floats towards the pinion when it spins it will still settle in the sweet spot.

[Nastyn8]

Got a brand new kit in the mail today. Guys like spunkybob and myself are just getting all this sorted out with the pinion. You other guys have dealt with it for years, so forgive us for keeping it ongoing.

My understanding so far is the pinion needs to back away from the ring gear. Doing the 3 bearing mod the space is shorter, so it’s backed away, which is the goal. First, I understand, too far away is bad, but why make up all the lost depth with more shims to match bearing spacer bearing? Doesn’t that just put it back in the same spot? But, I also understand the 3rd bearing helps the load.

So why not 3 bearings and slightly less shim?

[Nastyn8]

I guess it would be easier for me like this.

Stock bearing spacer bearing=12.82mm
3 bearing=12mm
Lost depth=.82mm

But instead of adding .82 we are just adding ~.6-.7 to back it up some?

[Tzicul]

Originally Posted by Nastyn8

I guess it would be easier for me like this.

Stock bearing spacer bearing=12.82mm
3 bearing=12mm
Lost depth=.82mm

But instead of adding .82 we are just adding ~.6-.7 to back it up some?

Yep! Trail and error until you find the sweet spot

[Nastyn8]

Awesome! I’m so excited for this kit. Thanks for the info. So does this go for the front and back?

[Tzicul]

Yes, they are absolutely the same.